MORPHOLOGICAL EVOLUTION OF A STABILIZED TIDAL INLET AND IMPLICATIONS FOR COASTAL INFRASTRUCTURE VULNERABILITY

Evolutionary patterns of a tidal inlet and its adjacent barrier islands are identified via 10 years of remotely sensed data, hydrographic surveys, and a morphological numerical model. A cyclical geometric adjustment of the inlet to dredging of its navigation channel indicates that the system is in stable equilibrium. The inlet has been experiencing a counterclockwise rotation likely caused by the growth of a spit and the presence of a terminal groin that restricts the inlet migration. As this rotation continues, the southernmost flood channel has been encroaching into the downdrift back barrier. Continued erosion along the estuarine shoreline could increase the vulnerability of an existing coastal roadway from the estuarine side.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/DCee7MlQkGI

Socioeconomic and environmental predictors of estuarine shoreline hard armoring

Rising sea levels and growing coastal populations are intensifying interactions at the land-sea interface. To stabilize upland and protect human developments from coastal hazards, landowners commonly emplace hard armoring structures, such as bulkheads and revetments, along estuarine shorelines. The ecological and economic consequences of shoreline armoring have garnered significant attention; however, few studies have examined the extent of hard armoring or identified drivers of hard armoring patterns at the individual landowner level across large geographical areas. This study addresses this knowledge gap by using a fine-scale census of hard armoring along the entire Georgia U.S. estuarine coastline. We develop a parsimonious statistical model that accurately predicts the probability of armoring emplacement at the parcel level based on a set of environmental and socioeconomic variables. Several interacting influences contribute to patterns of shoreline armoring; in particular, shoreline slope and the presence of armoring on a neighboring parcel are strong predictors of armoring. The model also suggests that continued sea level rise and coastal population growth could trigger future increases in armoring, emphasizing the importance of considering dynamic patterns of armoring when evaluating the potential effects of sea level rise. For example, evolving distributions of armoring should be considered in predictions of future salt marsh migration. The modeling approach developed in this study is adaptable to assessing patterns of hard armoring in other regions. With improved understanding of hard armoring distributions, sea level rise response plans can be fully informed to design more efficient scenarios for both urban development and coastal ecosystems.